In such an assembly it is customary to provide a hood which overlies the quenching wagon in its unloading position in order to catch the rising waste gases and lead them to a filtering or dedusting device separating entrained solids therefrom. While the charge is being pushed out of a coking chamber into the unloading carriage aligned therewith, the hood is connected with that carriage via a substantially airtight lateral channel traversed by a carbonaceous mass and the accompanying gases. In a conventional system, e.g. as described in German published specification (Offenlegungsschrift) No. 22 11 571, the waste gases are fed to a fixed wet-filtering unit via a stationary manifold to which the hood outlet must be tightly attached during unloading; the dedusting device described in that published specification includes a set of liquid filters. Another type of filter, formed by a heat-resistant cloth, is described in German patent application No. 28 42 655.3; according to that application, the cloth is periodically set in vibration for dislodging the intercepted solids which fall back onto the glowing coke bed. In this latter system, too, the exhaust gases are fed--after prefiltering--by way of a manifold to a central dedusting device with the aid of a suitably dimensioned blower.